Date: Mon, 30 Jul 2018 16:06:02 +0200 From: Tobias Urdin <tobias.urdin@binero.se> To: freebsd-net@freebsd.org Subject: ospf redistribute into openbgpd overwrites directly connected routes Message-ID: <9507d752-6815-92fe-924b-55459710bb9d@binero.se>
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Hello,
I have a setup where we connect a OSPF area with a edge router, this
edge router then has a BGP peer to my router
where it redistributes all OSPF routes into the BGP feed to my router.
My router is running FreeBSD 11.1 with openbgpd
root@myrouter:~ # uname -a
FreeBSD dr20-1-sto1 11.1-RELEASE FreeBSD 11.1-RELEASE #0 r321309: Fri
Jul 21 02:08:28 UTC 2017
root@releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC amd64
root@myrouter:~ # pkg info openbgpd
openbgpd-5.2.20121209_2
Name : openbgpd
Version : 5.2.20121209_2
The thing here is that my router has layer 2 access directly to one of
the networks that the edge router BGP announces to my router
(172.20.104.0/22).
When my FreeBSD machine boots it will install a directly connected route
for 172.20.104.0/22 in my routing table but as soon as openbgpd starts
it will
install a 172.20.104.0/22 route with the nexthop of the edge router instead.
How can I prevent openbgpd from overwriting the directly connected route?
Directly connected networks should never be overwritten by a routing
protocol but I suspect this is because of the redistribute.
I've tried messing with metrics, but maybe I to create a rtable and mess
around with that?
Output of some info is below.
Best regards
Tobias
root@myrouter:~ # bgpctl show fib connected | grep 104
*C 48 172.20.104.0/22 link#10
root@myrouter:~ # route get 172.20.104.100
route to: 172.20.104.100
destination: 172.20.104.0
mask: 255.255.252.0
gateway: edgerouter
fib: 0
interface: vlan10
flags: <UP,GATEWAY,DONE,PROTO1,PINNED>
recvpipe sendpipe ssthresh rtt,msec mtu weight expire
0 0 0 0 1500 1 0
root@myrouter:~ # ifconfig vlan10
vlan10: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST>
metric 0 mtu 1500
options=600703<RXCSUM,TXCSUM,TSO4,TSO6,LRO,RXCSUM_IPV6,TXCSUM_IPV6>
ether x
inet 172.20.107.253 netmask 0xfffffc00 broadcast 172.20.107.255
inet 172.20.107.254 netmask 0xfffffc00 broadcast 172.20.107.255
vhid 2
nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
media: Ethernet autoselect (10Gbase-Twinax
<full-duplex,rxpause,txpause>)
status: active
vlan: 10 vlanpcp: 0 parent interface: ix1
carp: MASTER vhid 2 advbase 1 advskew 10
groups: vlan
root@myrouter:~ # cat /etc/rc.conf
...snip..
ifconfig_vlan10="inet 172.20.107.253 netmask 255.255.252.0 vlan 10
vlandev ix1"
ifconfig_vlan10_alias0="inet vhid 2 advskew 100 pass test123 alias
172.20.107.254/22"
root@myrouter:~ # cat /usr/local/etc/bgpd.conf
...snip...
group "peering ASxxxx" {
remote-as xxxx
softreconfig in yes
neighbor edgerouter {
announce self
descr "AS xxxx edgerouter"
local-address xxxx
depend on <outside int>
}
}
...snip...
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